The overall objective of my work is to determine how the mammalian brain stem functions to integrate sensory inputs and intrinsic respiratory activity to produce an appropriate respiratory motor response. My efforts will concentrate upon the dorsal respiratory group (DRG) of neurons in the medulla of cat. I believe these cells are the initial intracranial processing station for many visceral reflexes affecting respiration. I intend to identify the sensory inputs to these cells and the role of these cells in reflex responses to these inputs. I will compare respiration and respiratory reflexes following focal destruction of the DRG in anesthetized-acute and awake-chronic experiments. I will employ partial vagal cold block and DRG neuronal recording to determine the nature of pulmonary sensory receptor inputs onto these cells. Microstimulation and collision testing will be used to directly demonstrate the presence of axonal projections between the DRG and pneumotaxic center. From the results I will establish the role and function in respiration of this key collection of brain stem neurons.